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Tuesday, December 9, 2008

GB3RAL and the Leonids Meteor Shower...17th Nov 2008

This is a post that I have been meaning to put up for a while. Now that the peak of the Geminids meteor shower is coming up next weekend (13th of Dec), now seems like a good time to put it up.

During the morning of the 17th of November which was supposed to be the peak of the Leonids meteor shower, I tried listening for the GB3RAL beacon in England on 28.215 MHz.

Equipment.....Kenwood TS690s tuned to 28.215.1 MHz on CW (500 Hz filter fitted)
Antenna........Half wave 10 metre vertical at 5 metres AGL
Distance......490 kms due East from here (IO91in<->IO51tu)

As well as listening by ear to the received signals, I put the microphone from the PC next to the rig and monitored the signal with the Spectrum Lab Audio Analyzer program.

After a while, I got a few audible pings that showed on the waterfall dislay so I could see that there was something there around 500 Hz.



At 09:24, I recorded what was the start of a long 5 to 6 minute burst. As you can see above, it started suddenly and after a few minutes, it began to slowly fade away. Listening by ear, I could just about hear that there was something there yet it showed up quite clearly on the waterfall display.

From what I could hear, there was no cw. It was just a constant carrier.


However when I looked at the display closer, I could see that the signal was about 7 Hz wide before finally becoming a narrower signal. I can see from beacon lists that the GB3RAL beacon uses FSK....i.e. the carrier moves in frequency to generate the CW rather than turning on and off. I asked the beacon keeper G0MJW about this and he informed me that the keyer on the beacon has failed and a replacement is under construction.

What I heard and saw was like the beacon keyer was still working (i.e. FSK) except that the frequency shift was now a lot lower than it should be (i.e. 7 Hz instead of say 300 Hz).

Q. Was it GB3RAL that I heard? Probably likely but to be honest, until I can get a positive ID, I will never be 100% sure. I might have a listen again during the Geminids and see how it goes.

Notes...
(1) The various other lines shown on the above displays are mainly just interference generated by the PC. Even though I can't hear them, they show up quite clearly on the display.

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